Expert appraisal of criteria for nonhuman primate substance use disorder models: An international Delphi study.

Background: A persistent challenge in substance use disorder (SUD) research is that no single animal model can fully recapitulate the multidimensional clinical features of the human disorder. Although nonhuman primates (NHPs) may provide greater translational relevance for modelling complex cognitive and behavioural features, there is currently no consensus on the core criteria for defining and evaluating NHP models of SUD. Aims: The Delphi approach used in this study aims to investigate expert perspectives in the field of SUD and to establish consensus on developing an NHP model that encompasses the core clinical features of SUD. Method: We used a Delphi approach to survey a pool of international experts in the field and reach a broad consensus through iterative consultation. Results: Forty experts were invited to participate in the survey; 25 agreed to participate, and 21 completed the first round and were included in the study. The first round discussed 12 potential diagnostic criteria items, and the second round discussed 8 items. The results showed that three items were deemed 'very important' or 'extremely important' and consistency remained stable after two survey rounds: (1) the subject spent more time or effort trying to procure the drug than the expected normative value; (2) the subject had high motivation (craving) to use the drug; and (3) relapse. Conclusions: The present study used the Delphi method to develop a subset of criteria for the NHP SUD model. This offers guidance for present and future researchers utilising NHP models to investigate the mechanisms of SUD.